The efficiency of Cre activation in CAG-CAT-Z transgenic embryos
| . | . | Number transferred . | Number implanted . | Number of blue embryos . | |||
|---|---|---|---|---|---|---|---|
| Injected DNA/protein . | . | Injection at the one-cell stage . | . | . | |||
| CMV Cre (pBS185) | 5 ng/μl | 169 | 69 | 3 (4.3%) | |||
| pCAG-Cre | 5 ng/μl | 28 | 20 | 6 (30%) | |||
| Cre recombinase | 10 ng/μl | 123 | 60 | 0 (0%) | |||
| . | . | Number transferred . | Number implanted . | Number of blue embryos . | |||
|---|---|---|---|---|---|---|---|
| Injected DNA/protein . | . | Injection at the one-cell stage . | . | . | |||
| CMV Cre (pBS185) | 5 ng/μl | 169 | 69 | 3 (4.3%) | |||
| pCAG-Cre | 5 ng/μl | 28 | 20 | 6 (30%) | |||
| Cre recombinase | 10 ng/μl | 123 | 60 | 0 (0%) | |||
| Injected DNA/proteinInjection at the two-cell stage . | . | . | . | . | ||||
|---|---|---|---|---|---|---|---|---|
| CMV Cre (pBS185) | 5 ng/μl | 295 | 180 | 3 (1.7%) | ||||
| pCAG-Cre | 5 ng/μl | 180 | 125 | 14 (11.2%) | ||||
| Cre recombinase | 10 ng/μl | 47 | 32 | 0 (0%) | ||||
| Injected DNA/proteinInjection at the two-cell stage . | . | . | . | . | ||||
|---|---|---|---|---|---|---|---|---|
| CMV Cre (pBS185) | 5 ng/μl | 295 | 180 | 3 (1.7%) | ||||
| pCAG-Cre | 5 ng/μl | 180 | 125 | 14 (11.2%) | ||||
| Cre recombinase | 10 ng/μl | 47 | 32 | 0 (0%) | ||||
Three types of methods for Cre activation were tested in the one-cell and the two-cell stage embryos. pBS185 or pCAG-Cre plasmids were injected into the nucleus of the embryo. After culturing for specified periods, healthy embryos were transferred into the uteri of pseudo-pregnant females. These embryos were recovered 8 days later and subjected to X-gal staining. The numbers and percentage of the X-gal-positive embryos are shown. pCAG-Cre gave the best results, 30% and 11.2% X-gal-positive embryos following injection at the one-cell stage, and at the two-cell stage respectively. We could not obtain X-gal-positive embryos after injections with Cre recombinase protein.